Two-filament incandescent lamp for non-dazzling high and low beams in automobile headlights



Aug. 10, 1965 TWO-FILAME'NT INGANIiESCENT LAMP FOR NON-DAZZLING RMICKLEY 3,200,281

HIGH AND LOW BEAMS IN AUTOMOBILE HEADLIGHTS Filed Oct. 8. 1962 F IG.I

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INVENTOR. Rolf Mickley ATTORNEYS.

United States Patent 1 tjlaim. oi. sis-air This application forinvention relates to a two-filament, incandescent lamp for automobileheadlights having nondazzling high and low beams, and is acontinuation-inpart of my application Serial No. 220,831 filed August31, 1962 and my application Serial No. 207,678 filed July 5, 1962.

Application Serial No. 207,678 discloses an incandescent lamp of thetype having a paraboloid reflector, a U-shaped highbeam filamentpositioned horizontally about the focal point of the reflector, and astraight down beam filament extending from behind the focal pointaxially toward the reflector. The feature of said application is theprovision of two shields which together prevent dazzling and are adaptedto radiate both a nondazzling high beam which is sharply focused in ahorizontal plane and a non-dazzling low beam that is of shorter rangeand downwardly directed. According to the disclosure a first of saidshields extends over the top of the portions of the filaments thatextend back of the focal point and under the portion of the filamentsthat extend in front of the focal point, the focal point not beingobscured.

Said application Serial No. 220,831 is a continuation-inpart ofapplication Serial No. 207,678 and discloses an incandescent lamp ofsubstantially identical construction to that of Serial No. 207,678 butspecifies that the interiors of the shielding means (facing thefilaments) are silvered while the exteriors thereof are frosted.

This invention is based on the discovery that it is also possible withonly one anti-dazzle shield to achieve the same illumination effect ashitherto with a system of two anti-dazzle shields. This has theadvantage that, on the one hand, even less shielding material needs tobe used and arranged inside the incandescent lamp and, on the otherhand, the reflection in the upper wall of the glass envelope and thehitherto resulting reflection in the lower half of the reflector, whichin part has a dazzling effect, is almost completely eliminated due tothe fact that, in accordance with the invention, the U-shaped high-beamfilament with its arc-shaped portion is moved back so far into the focalpoint or to a position where it encloses the focal point so closely thatthe anti-dazzle shield otherwise located in front of the focal point maybe dispensed with and hence the upper anti-dazzle shield located behindthe plane passing vertically through the optical axis and intersectingthe focal point is alone sulficient to give non-dazzling high and downbeams.

The schematic drawing illustrates the mode of operation of thisarrangement of parts.

FIG. 1 is a vertical, longitudinal section of a paraboloid reflector inthe operation position and indicates the path of the rays resulting fromthe geometric arrangement of the lamp parts.

FIG. 2 is a view from below the highand down-beam filaments withanti-dazzle shield and the exposed, 11nshielded arc of the U-shapedhigh-beam filament closely surrounding the focal point.

FIG. 3 is a view from above of the same assembly shown in FIG. 2,likewise with the exposed arc of the U-shaped high-beam filament closelysurrounding the focal point and the said anti-dazzle shield.

3,2 ,281 Patented Aug. 10, 1965 The two-filament lamp of the inventioncomprises a high-beam, U-shaped filament 6, disposed in a horizontalplane about the focal point 2, with the open end of filament 6 towardthe parabolic reflector, and a low-or-down beam filament 4 locatedbehind the focal point and between the arms of the high-beam filament.The curved portion of the high-beam filament is moved so far back intothe focal point, or is moved back to enclose the focal point so closely,that only an upper anti-dazzle shield 5 located behind the focal pointis required for non-dazzling high and down beams. This singleanti-dazzle shield extends forwardly to the plane 3 normal to theoptical axis 1, intersects the focal point and has its lateral edgesextending beyond the sides of the U-shaped filament and down to thehorizontal plane defined by the optical axis of the paraboloidreflector. Recesses may be provided in the anti-dazzle shield in thisarrangement if a lateral asymmetrical spread of the high and down beamsbeyond the horizontal plane determined by the optical axis is desired.Glare, especially when no recesses are provided in the anti-dazzleshield, is reduced to exactly the same extent for the high-beamfilaments as if the two anti-dazzle shields were installed. The solidangle of the upper half of the reflector which in such case producesdazzling radiation, is eliminated according to the struc ture of thepresent invention by the positioning of the two filaments with respectto the single shield and the focal point and produces the same effect asis obtained by the two shield device of said application Serial No.207,678, and in addition the radiation of the high-beam filamentproduces the optimum effect in accordance with the invention due to theexposed are at the focal point.

I claim:

In a non-dazzling incandescent lamp comprising two incandescent lampfilaments for high and down beams and a paraboloid reflector, theimproved anti-dazzling construction comprising as a high beamilluminating means, a coiled filament of Ushaped configuration with thearms of the U extending rearwardly with respect to the opening of saidparaboloid reflector,

said coiled filament of U-shaped configuration being positioned in thehorizontal plane of the optical axis of said paraboloid reflector withthe outer limits of the arm-connecting portion of the U-shaped filamentextending only slightly beyond the focal point of said paraboloidreflector,

a 10W beam illuminating means comprising a coiled filament of straightconfiguration said coiled filament of straight configuration positionedin the horizontal plane of the optical axis of said paraboloid reflectorand extending between the arms and to the rear of the central portion ofsaid filament of U-shaped configuration,

and a single anti-dazzle shield extending over that portion of saidfilaments back of the focal point of said reflector.

References Cited by the Examiner UNITED STATES PATENTS 1,280,626 10/18Ames 313-111 1,963,672 12/28 Schroeder 313--115 X 1,947,243 2/34 Born313-115 2,020,130 11/35 Astor 313-111 2,245,793 6/41 Kurlander 3131152,501,140 4/50 Pique 313-111 GEORGE N. WESTBY, Primary Examiner.

DAVID J. GALVIN, Examiner.

